Dart: Removes dartzip

examples/dart/hello_world/hello/BUILD.gn

 # Copyright 2015 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//mojo/public/dart/rules.gni")
 
-dartzip_packaged_application("mojo_dart_hello_dartzip") {
-  output_name = "mojo_dart_hello"
-  sources = [
-    "lib/main.dart",
-    "pubspec.yaml",
-  ]
-  deps = [
-    "//mojo/public/dart:dart_dartzip",
-  ]
-}
-
-dart_pkg("mojo_dart_hello_pkg") {
+dart_pkg("hello") {
   apps = [ "lib/main.dart" ]
+  app_name_override = "dart_hello"
   sources = [
     "pubspec.yaml",
   ]
   deps = [
     "//mojo/public/dart",
   ]
 }
-
-group("hello") {
-  deps = [
-    ":mojo_dart_hello_dartzip",
-    ":mojo_dart_hello_pkg",
-  ]
-}